B-stage

A secondary stage in the reaction of some
thermosetting resins, characterized by softening
of the resin when heated and swelling when in the
presence of certain liquids. but without complete
fusing or dissolving. The "b-stage" is also
characterized by a progressive increase in
viscosity. The resin portion of an uncured
thermosetting adhesive is usually in this stage.
Also called "resitol." See also: A-STAGE ; C-STAGE . (309 )